Streaming breakpoint for data tuples that stay in an operator graph too long

ABSTRACT

A streams manager monitors data tuples processed by a streaming application represented by an operator graph. The streams manager includes a tuple breakpoint mechanism that allows defining a tuple breakpoint that fires when a tuple has been in the operator graph too long. What constitutes too long can be defined in a number of different ways, including a time limit, a processing limit for multiple operators, and a processing limit for an individual operator. When the tuple breakpoint fires, one or more operators in the operator graph are halted according to specified halt criteria. Information corresponding to the breakpoint that fired is then displayed. The tuple breakpoint mechanism thus provides a way to debug a streaming application that may have data tuples that stay in the operator graph too long.

BACKGROUND

1. Technical Field

This disclosure generally relates to streaming applications, and more specifically relates to enhancing debugging of a streaming application using breakpoints for data tuples that stay in an operator graph too long.

2. Background Art

Streaming applications are known in the art, and typically include multiple operators coupled together in an operator graph that process streaming data in near real-time. An operator typically takes in streaming data in the form of data tuples, operates on the data tuples in some fashion, and outputs the processed data tuples to the next operator. Streaming applications are becoming more common due to the high performance that can be achieved from near real-time processing of streaming data.

Many streaming applications require significant computer resources, such as processors and memory, to provide the desired near real-time processing of data. However, the workload of a streaming application can vary greatly over time. Allocating on a permanent basis computer resources to a streaming application that would assure the streaming application would always function as desired (i.e., during peak demand) would mean many of those resources would sit idle when the streaming application is processing a workload significantly less than its maximum. Furthermore, what constitutes peak demand at one point in time can be exceeded as the usage of the streaming application increases. For a dedicated system that runs a streaming application, an increase in demand may require a corresponding increase in hardware resources to meet that demand.

Cloud-based streaming is known in the art. Known systems for cloud-based streaming do not monitor data tuples to determine when a tuple has been in an operator graph too long.

BRIEF SUMMARY

A streams manager monitors data tuples processed by a streaming application represented by an operator graph. The streams manager includes a tuple breakpoint mechanism that allows defining a tuple breakpoint that fires when a tuple has been in the operator graph too long. What constitutes too long can be defined in a number of different ways, including a time limit, a processing limit for multiple operators, and a processing limit for an individual operator. When the tuple breakpoint fires, one or more operators in the operator graph are halted according to specified halt criteria. Information corresponding to the breakpoint that fired is then displayed. The tuple breakpoint mechanism thus provides a way to debug a streaming application that may have data tuples that stay in the operator graph too long.

The foregoing and other features and advantages will be apparent from the following more particular description, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The disclosure will be described in conjunction with the appended drawings, where like designations denote like elements, and:

FIG. 1 is a block diagram of a cloud computing node;

FIG. 2 is a block diagram of a cloud computing environment;

FIG. 3 is a block diagram of abstraction model layers;

FIG. 4 is a block diagram showing some features of a streams manager;

FIG. 5 is a table showing some suitable examples of breakpoint criteria for a tuple breakpoint that define when a tuple has been in the operator graph too long;

FIG. 6 is a table showing some suitable examples of halt criteria that could be specified for a tuple breakpoint;

FIG. 7 is a table showing some suitable examples of information that could be displayed when a tuple breakpoint fires;

FIG. 8 is a flow diagram of a method for defining a tuple breakpoint;

FIG. 9 is a flow diagram of a method for processing a tuple breakpoint when it fires;

FIG. 10 is a block diagram showing a specific example of an operator graph corresponding to a streaming application;

FIG. 11 is a table showing tuple breakpoint criteria for the specific example in FIG. 10; and

FIG. 12 is a table showing halt criteria for the tuple breakpoint shown in FIG. 11.

DETAILED DESCRIPTION

The disclosure and claims herein relate to a streams manager that monitors data tuples processed by a streaming application represented by an operator graph. The streams manager includes a tuple breakpoint mechanism that allows defining a tuple breakpoint that fires when a tuple has been in the operator graph too long. What constitutes too long can be defined in a number of different ways, including a time limit, a processing limit for multiple operators, and a processing limit for an individual operator. When the tuple breakpoint fires, one or more operators in the operator graph are halted according to specified halt criteria. Information corresponding to the breakpoint that fired is then displayed. The tuple breakpoint mechanism thus provides a way to debug a streaming application that may have data tuples that stay in the operator graph too long.

It is understood in advance that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed.

Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service's provider.

Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.

Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for loadbalancing between clouds).

A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure comprising a network of interconnected nodes.

Referring now to FIG. 1, a block diagram of an example of a cloud computing node is shown. Cloud computing node 100 is only one example of a suitable cloud computing node and is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the invention described herein. Regardless, cloud computing node 100 is capable of being implemented and/or performing any of the functionality set forth hereinabove.

In cloud computing node 100 there is a computer system/server 110, which is operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with computer system/server 110 include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like.

Computer system/server 110 may be described in the general context of computer system executable instructions, such as program modules, being executed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks or implement particular abstract data types. Computer system/server 110 may be practiced in distributed cloud computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computer system storage media including memory storage devices.

As shown in FIG. 1, computer system/server 110 in cloud computing node 100 is shown in the form of a general-purpose computing device. The components of computer system/server 110 may include, but are not limited to, one or more processors or processing units 120, a system memory 130, and a bus 122 that couples various system components including system memory 130 to processor 120.

Bus 122 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

Computer system/server 110 typically includes a variety of computer system readable media. Such media may be any available media that is accessible by computer system/server 110, and it includes both volatile and non-volatile media, removable and non-removable media.

System memory 130 can include computer system readable media in the form of volatile, such as random access memory (RAM) 134, and/or cache memory 136. Computer system/server 110 may further include other removable/non-removable, volatile/non-volatile computer system storage media. By way of example only, storage system 140 can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a “hard drive”). Although not shown, a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a “floppy disk”), and an optical disk drive for reading from or writing to a removable, non-volatile optical disk such as a CD-ROM, DVD-ROM or other optical media can be provided. In such instances, each can be connected to bus 122 by one or more data media interfaces. As will be further depicted and described below, memory 130 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions described in more detail below.

Program/utility 150, having a set (at least one) of program modules 152, may be stored in memory 130 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data. Each of the operating system, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment. Program modules 152 generally carry out the functions and/or methodologies of embodiments of the invention as described herein.

Computer system/server 110 may also communicate with one or more external devices 190 such as a keyboard, a pointing device, a display 180, a disk drive, etc.; one or more devices that enable a user to interact with computer system/server 110; and/or any devices (e.g., network card, modem, etc.) that enable computer system/server 110 to communicate with one or more other computing devices. Such communication can occur via Input/Output (I/O) interfaces 170. Still yet, computer system/server 110 can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via network adapter 160. As depicted, network adapter 160 communicates with the other components of computer system/server 110 via bus 122. It should be understood that although not shown, other hardware and/or software components could be used in conjunction with computer system/server 110. Examples, include, but are not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data archival storage systems, etc.

Referring now to FIG. 2, illustrative cloud computing environment 200 is depicted. As shown, cloud computing environment 200 comprises one or more cloud computing nodes 100 with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone 210A, desktop computer 210B, laptop computer 210C, and/or automobile computer system 210N may communicate. Nodes 100 may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment 200 to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices 210A-N shown in FIG. 2 are intended to be illustrative only and that computing nodes 100 and cloud computing environment 200 can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser).

Referring now to FIG. 3, a set of functional abstraction layers provided by cloud computing environment 200 (FIG. 2) is shown. It should be understood in advance that the components, layers, and functions shown in FIG. 3 are intended to be illustrative only and the disclosure and claims are not limited thereto. As depicted, the following layers and corresponding functions are provided.

Hardware and software layer 310 includes hardware and software components. Examples of hardware components include mainframes 352; RISC (Reduced Instruction Set Computer) architecture based servers 354; servers 356; blade servers 358; storage devices 360; and networks and networking components 362. In some embodiments, software components include network application server software 364 and database software 366.

Virtualization layer 320 provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers 368; virtual storage 370; virtual networks 372, including virtual private networks; virtual applications and operating systems 374; and virtual clients 376.

In one example, management layer 330 may provide the functions described below. Resource provisioning 378 provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing 380 provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may comprise application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal 382 provides access to the cloud computing environment for consumers and system administrators. Service level management 384 provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment 386 provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. The management layer further includes a streams manager (SM) 350 as described herein. While the streams manager 350 is shown in FIG. 3 to reside in the management layer 330, the streams manager 350 actually may span other levels shown in FIG. 3 as needed.

Workloads layer 340 provides examples of functionality for which the cloud computing environment may be utilized. Examples of workloads and functions which may be provided from this layer include: mapping and navigation 388; software development and lifecycle management 390; virtual classroom education delivery 392; data analytics processing 394; transaction processing 396 and mobile desktop 398.

As will be appreciated by one skilled in the art, aspects of this disclosure may be embodied as a system, method or computer program product. Accordingly, aspects may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a non-transitory computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

FIG. 4 shows one suitable example of the streams manager 350 shown in FIG. 3. The streams manager 350 is software that manages one or more streaming applications, including creating operators and data flow connections between operators in an operator graph that represents a streaming application. The streams manager 360 includes a performance monitor 410 and a tuple breakpoint mechanism 450. The performance monitor 410 preferably includes a tuple monitor 420, one or more thresholds 430, and one or more historical logs 440. The tuple monitor monitors data tuples processed by operators in an operator graph, and logs the monitored information in historical log(s) 440. The thresholds 430 may include any suitable criteria, including criteria that determines when a tuple breakpoint fires. Thus, in one implementation, the performance monitor 410 may compare the data in the historical log(s) 440 to the threshold(s) 430 and may then signal the tuple breakpoint mechanism 450 that the threshold(s) 430 have been satisfied, causing a tuple breakpoint to fire in the tuple breakpoint mechanism 450. In an alternative implementation, the threshold(s) 430 in the performance monitor are not related to breakpoint processing, with the tuple breakpoint mechanism 450 determining when a defined tuple breakpoint 460 fires based on information in the historical log(s) 440 of the performance monitor. The tuple breakpoint 460 preferably specifies at least one breakpoint criterion. Suitable examples of breakpoint criteria for tuple breakpoint 460 are shown in FIG. 5 to include a time limit for a tuple 510, a multiple operator processing limit for a tuple 520, and an individual operator processing limit for a tuple 530. A time limit for a tuple 510 preferably specifies a time that is considered “too long” for a tuple to remain in the operator graph. This time could be specified from the time the tuple was created, or from the time the tuple was first operated on by an operator in the operator graph. The multiple operator processing limit for a tuple 520 specifies a threshold for a group of operators that process the tuple. For a relatively complex operator graph, this would allow operators to be grouped to determine when all of the operators have processed a tuple a specified number of times. An individual operator processing limit for a tuple 530 preferably specifies a threshold number of times a particular operator can process a tuple. Note that many different tuple breakpoints could be active at the same time. Thus, three breakpoints that specify 510, 520 and 530 could all be active at the same time. In addition, a single breakpoint could be defined with any suitable combination of criteria. For example, a breakpoint could be defined to fire when a time limit for a tuple 510 is reached OR when an individual operator processing limit for a tuple 530 is reached. In another example, a breakpoint could be defined to fire when a time limit for a tuple 510 is reached AND when an individual operator processing limit for a tuple 530 is reached. The criteria in FIG. 5 for tuple breakpoint are shown by way of example, and are not limiting. The disclosure and claims herein expressly extend to any suitable criteria, including combinations of criteria, that can determine when a tuple breakpoint fires. For the discussion herein the criteria used to define a tuple breakpoint specify conditions under which it is determined the tuple has been in the operator graph too long. As discussed above, this concept of “too long” can be defined in any suitable way using any suitable criteria, combination of criteria, algorithm or heuristic.

Referring again to FIG. 4, the tuple breakpoint mechanism 450 includes an operator halt mechanism 470 that is used when a tuple breakpoint 460 fires. The operator halt mechanism 470 defines at least one halt criterion, shown as halt criteria 472 in FIG. 4, which specifies one or more operators to halt when a breakpoint fires. Suitable examples of halt criteria 472 are shown in FIG. 6 to include halt all operators 610; halt a defined list of operators 620; halt an operator that caused a breakpoint 630; halt an operator that used the most amount of time 640; and halt an operator that executed the tuple the greatest number of times 650. Note that halting a defined list of operators 620 can include halting all operators 610 when all operators are on the defined list. In one suitable implementation, each defined tuple breakpoint 460 has its own corresponding halt criteria 472. However, in a different implementation, halt criteria 472 could apply to all breakpoints, or to a specified subset of breakpoints.

The tuple breakpoint display mechanism 480 in FIG. 4 displays to a user tuple breakpoint display information 482. Examples of the tuple breakpoint display information 482 are shown in FIG. 7 to include: when the tuple was created 710; the time the tuple has been in the operator graph 720; the number of operators that processed the tuple 730; and a list of operators that processed the tuple and how many times 740. This information can help a user debug a streaming application when data tuples are staying in an operator graph for too long.

Data tuples can stay in an operator graph too long when the operator graph includes at least one feedback path that routes data tuples to a previous operator in the operator graph. However, in a simple linear operator graph, there can also a threat of data tuples staying in the operator graph too long. For example, if one of the operators is a join operator, a tuple could remain in the operator graph too long. The disclosure and claims herein apply to any operator graph where a tuple can stay in the operator graph too long.

FIG. 8 shows a method 800 for defining a tuple breakpoint, such as tuple breakpoint 460 shown in FIGS. 4 and 5. At least one breakpoint criterion is defined (step 810). At least one halt criterion is defined (step 820). Tuple breakpoint display information is also defined (step 830). Method 800 is then done. With the tuple breakpoint defined as shown in method 800 in FIG. 8, the streaming application can be executed. When the breakpoint criteria defined in step 810 is satisfied, the tuple breakpoint fires.

Referring to FIG. 9, a method 900 shows what happens when a tuple breakpoint fires. As long a no tuple breakpoint fires (step 910=NO), method 900 loops back and continues monitoring. When a tuple breakpoint fires (step 910=YES), one or more operators in the operator graph are halted according to the defined halt criteria (step 920), and the tuple breakpoint display information is displayed (step 930). Method 900 is then done.

A simple example is provided in FIGS. 10-12 to illustrate the concepts discussed above. A simple operator graph 1000 is shown in FIG. 10 to include four operators, A, B, C and D. Operator A is a source of data tuples. Operator B processes data tuples received from Operator A and also processes data tuples received from Operator C. Operator C processes data tuples received from Operator B, and output data tuples either to Operator D or to Operator B for further processing. In this simple example, we assume Operator C includes logic to determine whether a tuple has been sufficiently processed or not. If a tuple has been sufficiently processed, the tuple is output to Operator D, which is a sink for operators. If the tuple has not been sufficiently processed, the tuple is fed back to Operator B, which processes the tuple again. Because of this feedback path from operator C to Operator B, it is possible for data tuples to remain in the operator graph 1000 too long.

Referring to FIG. 11, we assume for this simple example a tuple breakpoint 1110 is defined that fires when operator C executes the same tuple more than 50 times 1120. Tuple breakpoint 1110 in FIG. 11 is one suitable example for tuple breakpoint 460 shown in FIGS. 4 and 5. This means a threshold of 50 is set for Operator C. On the 51st time that Operator C executes the same tuple, as determined by the historical log(s) 440 in the performance monitor 410, the tuple breakpoint 1110 fires to indicate the tuple has been in the operator graph too long. For the simple example in FIGS. 10-12, we assume halt criteria 1210 in FIG. 12 is defined that halts all operators 610. Thus, when the tuple breakpoint 1110 fires on the 51st time that operator C processes the tuple, all operators, namely, A, B, C and D in the operator graph 1000, are halted. Once all the operators are halted, any suitable information can be displayed to a user, including any or all of the tuple breakpoint display info shown in FIG. 7. Of course, other information not shown in FIG. 7 could also be displayed to the user when a breakpoint fires.

The tuple breakpoint mechanism disclosed and claimed herein provides an incredibly powerful and flexible way to debug streaming applications by detecting when data tuples have been in the operator graph too long.

The disclosure and claims herein relate to a streams manager that monitors data tuples processed by a streaming application represented by an operator graph. The streams manager includes a tuple breakpoint mechanism that allows defining a tuple breakpoint that fires when a tuple has been in the operator graph too long. What constitutes too long can be defined in a number of different ways, including a time limit, a processing limit for multiple operators, and a processing limit for an individual operator. When the tuple breakpoint fires, one or more operators in the operator graph are halted according to specified halt criteria. Information corresponding to the breakpoint that fired is then displayed. The tuple breakpoint mechanism thus provides a way to debug a streaming application that may have data tuples that stay in the operator graph too long.

One skilled in the art will appreciate that many variations are possible within the scope of the claims. Thus, while the disclosure is particularly shown and described above, it will be understood by those skilled in the art that these and other changes in form and details may be made therein without departing from the spirit and scope of the claims. 

The invention claimed is:
 1. A computer-implemented method executed by at least one processor for debugging a streaming application, the method comprising: executing a streaming application that comprises an operator graph that includes a plurality of operators that process a plurality of data tuples; monitoring each of the plurality of data tuples processed by the plurality of operators in the operator graph to determine time for the plurality of operators to process each of the plurality of data tuples and a number of times each of the plurality of operators process each of the plurality of data tuples; defining a tuple breakpoint that fires when at least one of the plurality of data tuples has been processed more than a specified limit for processing the at least one data tuple by all of the plurality of operators that process the at least one data tuple; and when the tuple breakpoint fires, halting at least one operator in the operator graph and displaying information regarding a data tuple that caused the tuple breakpoint to fire.
 2. The method of claim 1 wherein the specified limit comprises a time limit for processing the at least one data tuple.
 3. The method of claim 1 wherein the specified limit comprises a number of times for at least two of the plurality of operators in the operator graph to process the at least one data tuple.
 4. The method of claim 1 wherein the specified limit comprises a number of times for an individual operator in the operator graph to process the at least one data tuple.
 5. The method of claim 1 wherein the tuple breakpoint halts a defined list of operators in the operator graph when the tuple breakpoint fires.
 6. The method of claim 1 wherein the tuple breakpoint halts an operator in the operator graph that caused the tuple breakpoint to fire.
 7. The method of claim 1 wherein the tuple breakpoint halts an operator in the operator graph that used the most amount of time processing the data tuple that caused the tuple breakpoint to fire.
 8. The method of claim 1 wherein the tuple breakpoint halts an operator in the operator graph that processed the most times the data tuple that caused the tuple breakpoint to fire.
 9. The method of claim 1 wherein the tuple breakpoint displays information regarding the data tuple that caused the tuple breakpoint to fire, wherein the displayed information comprises at least one of: when the data tuple that caused the tuple breakpoint to fire was created; time the data tuple that caused the tuple breakpoint to fire was in the operator graph; number of operators that processed the data tuple that caused the tuple breakpoint to fire; list of operators that processed the data tuple that caused the tuple breakpoint to fire; and how many times each operator in the list processed the data tuple that caused the tuple breakpoint to fire.
 10. A computer-implemented method executed by at least one processor for debugging a streaming application, the method comprising: executing a streaming application that comprises an operator graph that includes a plurality of operators that process a plurality of data tuples; monitoring each of the plurality of data tuples processed by the plurality of operators in the operator graph to determine time for the plurality of operators to process each of the plurality of data tuples and a number of times each of the plurality of operators process each of the plurality of data tuples; defining a tuple breakpoint that fires when at least one of the plurality of data tuples has been processed more than a specified limit for processing the at least one data tuple by all of the plurality of operators that process the at least one data tuple when at least one of the following is satisfied: a time limit for processing the at least one data tuple; a number of times for at least two of the plurality of operators in the operator graph to process the at least one data tuple; and a number of times for an individual operator in the operator graph to process the at least one data tuple; when the tuple breakpoint fires, halting at least one of: all operators in the operator graph; a defined list of operators in the operator graph; an operator in the operator graph that caused the tuple breakpoint to fire; an operator in the operator graph that used the most amount of time processing the tuple that caused the tuple breakpoint to fire; and an operator in the operator graph that processed the tuple that caused the tuple breakpoint to fire the most times; displaying information regarding a tuple that caused the tuple breakpoint to fire, wherein the displayed information comprises: when the data tuple that caused the tuple breakpoint to fire was created; time the data tuple that caused the tuple breakpoint to fire was in the operator graph; number of operators that processed the data tuple that caused the tuple breakpoint to fire; list of operators that processed the data tuple that caused the tuple breakpoint to fire; and how many times each operator in the list processed the data tuple that caused the tuple breakpoint to fire.
 11. A computer-implemented method executed by at least one processor for debugging a streaming application, the method comprising: executing a streaming application that comprises an operator graph that includes a plurality of operators that process a plurality of data tuples; monitoring each of the plurality of data tuples processed by the plurality of operators in the operator graph to determine time for the plurality of operators to process each of the plurality of data tuples and a number of times each of the plurality of operators process each of the plurality of data tuples; defining a tuple breakpoint that fires when at least one of the plurality of data tuples has been-processed more than a specified limit for processing the at least one data tuple by all of the plurality of operators that process the at least one data tuple; and when the tuple breakpoint fires, halting an operator in the operator graph that processed the most times the data tuple that caused the tuple breakpoint to fire without halting all of the plurality of operators; and displaying information regarding a tuple that caused the tuple breakpoint to fire, wherein the displayed information comprises when the data tuple that caused the tuple breakpoint to fire was created.
 12. The method of claim 11 wherein the displayed information further comprises time the data tuple that caused the tuple breakpoint to fire was in the operator graph.
 13. The method of claim 12 wherein the displayed information further comprises a number of operators that processed the data tuple that caused the tuple breakpoint to fire.
 14. The method of claim 13 wherein the displayed information further comprises a list of operators that processed the data tuple that caused the tuple breakpoint to fire.
 15. The method of claim 14 wherein the displayed information further comprises how many times each operator in the list processed the data tuple that caused the tuple breakpoint to fire. 